Coalbed methane in the Powder River Basin is produced by microscopic bacteria breaking down organic materials. What if those microbes could be encouraged to make the natural gas faster and for an extended period of time?
The country could have a long-term energy source.
Researchers at Argonne National Laboratory, with help from the Montana Bureau of Mines and Geology, are exploring that possibility.
"Our early results look very promising," said Seth Snyder, Argonne's section leader of Chemical and Biological Technology.
Snyder's team has done initial work on coal from the region and tested its chemical theories on microbes in sewage sludge. "It definitely looks like they're accelerating methane production," he said.
Now it's time to try those theories on actual microbes or "bugs" from a coalbed methane well.
John Wheaton, a hydrogeologist, and Jay Gunderson, a coal geologist, both with the Montana Bureau of Mines and Geology, recently collected microbe samples for Argonne from wells being drilled by Nance Petroleum Corp. on a ranch in northern Wyoming.
Grabbing microbe samples requires patience and timing. The Montana scientists studied well logs from area wells and got down and dirty.
"We're trying to figure out when to expect the next coal beds based on what we already know about recent drilling in this area," Gunderson said, reading well logs.
Gunderson held a strainer under the rig's discharge pipe to catch drill cuttings and mud and examined the sample for coal.
Gunderson and Wheaton also checked piles of cuttings plopped in rows on the ground by the drillers. The piles are samples taken about every 10 feet and track the depth of the drill and what it is cutting. Shale layers are gray, while coal layers are black.
Pointing to the piles, Wheaton said, "The bugs in this would be damaged if not dead by now sitting out here in the air and sun, so that's why we have to make sure we get fresh samples right out of the line."
Because the microbes live in an anaerobic environment - one without oxygen - exposure to air kills them.
The microbes, Gunderson said, are tiny bacteria that chew up the coal or anything else with carbon in it and produce the methane. Making methane is "actually a complex reaction in multiple steps by a whole community of those little microbes," he said.
One coal seam about 500 feet deep, the Dietz layer, was too thin to be of much use for snatching microbe samples. So Wheaton and Gunderson waited more than an hour for the Canyon coal layer, which was more than 250 feet deeper.
Donning blue rubber gloves, Wheaton and Gunderson crouched at the end of the discharge pipe and scooped cuttings into a plastic bottle, filling it quickly and screwing on the lid. They placed the bottle in cooler and got ready to grab another sample.
In all, the scientists collected 16 one-liter samples from two coal seams. The samples were shipped to Argonne on Friday.
Argonne, located 25 miles southwest of Chicago, is one of the U.S. Department of Energy's largest research centers.
Argonne is studying the biology and the water chemistry of the microbes and theories by Ratin Datta, the lab's chemical engineer, Snyder said. Understanding the chemistry and physical conditions of the microbial community is key to determining the right conditions to help the microbes become rapid producers of methane, he said.
Coalbed methane in the Powder River Basin is found in coal seams and dates back 60 million years, to when the Rocky Mountains uplifted. Early mammals were expanding their range, and coal was forming in the Powder River and Williston basins of Eastern Montana, northern Wyoming and North Dakota. The area had large river systems and massive swamps, Wheaton said.
The basin's methane is formed through a biological process of decomposing organic materials. The "bugs" break down vegetation like fallen leaves or trees and produce methane as a byproduct.
As organic material got buried by more vegetation and sediment, it became compressed and gradually turned into peat. Rivers flooded and covered the area with sands and clays, sealing the peat and trapping the gas. As the long process continued and more organic material got buried, the peat eventually turned into coal.
Mining for methane requires drilling a series of wells into coal seams and depressurizing the aquifer by pumping ground water to the surface. The life of a coalbed methane well can vary, but some estimates are 20 years for wells in the Powder River Basin.
Argonne, and other laboratories, are trying to find ways to enhance the microbes. Based on the large volume of coal in the basin, enhancing microbes could extend methane production by several hundred years according to some estimates, Snyder said.
Research on anaerobic microbes in the basin by Luca Technologies, Inc., a privately held company in Denver, Colo., suggests that the basin's gas need not be ancient, but instead is being actively produced, according to Associated Press reports. Luca scientists say that methane production can be increased or decreased by altering the microbes' access to water or nutrients, or that production can be halted by exposing the organisms to oxygen or heat sterilization.
The microbes are a specialized community of "bugs," Snyder said. To live, the microbes need water, carbon and an energy source, all of which are found in the coal seams.
Snyder declined to comment on what role sodium in the ground water may play in Argonne's research but said, "Understanding the chemistry is the critical thing."
Ground water produced by coalbed methane wells in the northern part of the basin runs high in sodium. Irrigators worry that dumping the produced water into creeks or rivers may pollute the water and damage their soil and crops.
"We have an idea that really gets to the heart of what is the limiting factor in methane production," Snyder said.
Details on Argonne's theory and why it works won't be disclosed until the lab files for a patent and publishes its findings.
"We think we have an interest in the technology," Snyder said. If Argonne publishes its technology before getting a patent, anyone can run with its ideas and not need the lab as a partner, he said. Or someone else could seek a patent and then do nothing.
The United States has an interest in energy development, and Argonne wants to participate in its idea, Snyder said. If the technology is good, Argonne can license it to other companies. The national lab would receive a small royalty, which would pay for new research projects, he said. "We're not going to manufacture anything. We try to be enablers."
Argonne is working on proving its concept and is planning to file for a patent this year, Snyder said. This stage of the research is costing about $50,000. The next phase would cost several million dollars and involve working with partners, he said.
Contact Clair Johnson at firstname.lastname@example.org or 657-1282.